.IGES File

The iges file extension is commonly used for files in International Graphics Exchange Standard (IGES), an ANSI-approved standard format used with 3D wire frame models originally created in 1979.

One must be very careful when sourcing CAD files from all of today's modern CAD packages, as most/many of them export the long-obsolete "Surfaces NURBS" variation (few people know these differences). There are 3 primary versions of IGES: the 1980's "Bounded Surfaces", the 1990s "Surfaced NURBS" and the 2000's modern "BREP Manifold Solids". One should only export an IGES file in the latter "BREP Manifold Solids" version of IGES. If you try to convert via "Surfaced NURBS" (which has no BREP topology) then the model will be exploded into thounsads of individual NURBS patches, leading to patch cracking, flipped or randomly oriented surfaces, inverted vertex normals (for smoothing) and black banding effects. People on forums often complain that IGES is not a good CAD conversion file format but that is only because they are using the wrong version and/or poor 3D IGES importers. Note: IGES files are limited to a file size of 2GB due to their limited internal numeric range. 

The igs file contains IGES 2S or 3D CAD model.

MIME types:
application/iges
model/iges

Files with igs extension can be typically found as 3D graphics data saved in International Graphics Exchange Standard (IGES) format used for data exchange.

How to open:

Usually *.igs files can be imported to several CAD programs such as CATIA or Autodesk AutoCAD (might require plugin).

How to convert:

Most of the modern CAD/3D modeling programs support IGS/IGES format.